Recently mobile communication networks have started to support transmission of packet switched data or packet data in addition to traditional circuit switched data transmission.
An example of a technique allowing packet data transmission for mobile communication networks is General Packet Radio Service (GPRS). GPRS is designed to support e.g. digital mobile telecommunication networks based on the Global System for Mobile Communications (GSM) standard. However, GPRS is not restricted to only GSM networks but may support for example 3rd Generation Partnership Project (3GPP) based digital mobile telecommunication networks. Other examples of packet data based mobile communication networks are Wireless Local Area Network (WLAN) based mobile communication networks, Code Division Multiple Access (CDMA) based mobile communications networks, Wideband Code Division Multiple Access (WCDMA) based mobile communications networks, and Enhanced Data Rates for Global Evolution (EDGE) based mobile communication networks.
A GPRS based mobile communication network comprises supplementary network elements or nodes in addition to existing network elements. These include a Serving GPRS Support Node (SGSN) and a Gateway GPRS Support Node (GGSN). A Serving GPRS Support Node typically delivers packets to and from GPRS enabled terminal devices within its service area. A Gateway GPRS Support Node is typically used as an interface to external IP networks such as the Internet, other mobile service providers' GPRS services, or enterprise intranets.
The introduction of packet data based mobile communication networks has resulted in various value-added subscriber services being provided for these packet data based mobile communication networks. Examples of such subscriber services are packet data based voice, email, content downloading, browsing, streaming and rich calls. Furthermore, packet data based mobile communications networks typically offer network services to support the usage of subscriber services. Such network services include e.g. rerouting, barring, accounting, content proxy services, content blocking services, firewall services, virus scanning services, performance enhancement proxy services, Virtual Private Network (VPN) services, various Quality of Service (QoS) related services and various charging related services for both online and offline charging.
A recent trend is to provide the various subscriber and network services for packet data based mobile communications networks in a subscriber specific manner. To allow this, one or more subscription profiles are generated for each subscriber. The subscription profile comprises subscriber specifically customized subscription data that will be utilized in providing the various subscriber and network services to the terminal devices of the subscriber. The subscription data may comprise e.g. authorization information about which access points in the mobile communication network the subscriber is allowed to access, and which services are allowed within each allowed access point. The subscription data may further comprise e.g. information about charging attributes or rules, Quality of Service attributes or rules, and service chaining attributes such as attributes or rules for chained service selection and chained service component specific attributes or rules. An access point may be e.g. a Gateway GPRS Support Node of a General Packet Radio Service based mobile communication network, or a Packet Data Gateway of a Wireless Local Area Network based mobile communication network.
Prior art teaches storing the generated subscription profile in a subscriber database of a home network of the subscriber. As is known in the art, in the context of mobile communication networks, when a subscriber connects via a service area that is managed by an operator other than the one with whom the subscriber originally registered with, the subscriber is said to be “roaming”. In contrast, when the subscriber connects via a service area that is managed by the operator with whom the subscriber originally registered with, the subscriber is said to be at “home”. The mobile communication network managed by the operator with whom the subscriber originally registered with is called the home network of the subscriber. The subscriber database may be, for example, a Home Location Register in a General Packet Radio Service based mobile communication network.
The prior art solution of storing the generated subscription profile in the subscriber database of the home network of the subscriber works reasonably well while the subscriber is at home.
However, problems arise when the subscriber is roaming. When the terminal device of the subscriber roams into a visited network and requests to use a gateway of the visited network, the gateway needs to acquire the subscription profile of the roaming terminal device. Prior art teaches ways of acquiring the subscription profile. A way involves the gateway of the visited network directly contacting the subscriber database of the home network of the roaming terminal device and requesting the subscription profile of the roaming terminal device. Another way involves the gateway of the visited network first contacting a session control means of the home network of the roaming terminal device and requesting the subscription profile of the roaming terminal device. The session control means in turn contacts the subscriber database of the home network of the roaming terminal device, requests the subscription profile of the roaming terminal device, and forwards relevant parts of the subscription profile to the gateway of the visited network. Yet another way involves the gateway of the visited network contacting the session control means of the visited network, and the session control means of the visited network contacting the subscriber database of the home network and requesting the subscription profile of the roaming terminal device. The session control means is sometimes also referred to as Internet Protocol Session Control, a Policy Decision Function (PDF), a Charging Rules Function (CRF) or a Policy and Charging Control Node (PCCN).
Thus, in the prior art, when the terminal device is roaming and its subscription profile is required, the subscription profile will always have to be transmitted from one network to another, i.e. from the home network to the visited network. This, however, is not desirable. Transmitting the subscription profile from one network to another requires real-time signaling which in turn causes delay. In today's highly loaded mobile communication networks real-time signaling and its associated delay is to be avoided whenever possible. Furthermore, transmitting the subscription profile from one network to another may not even be possible at all times due to e.g. some connection problem between the two networks. Furthermore, the transmission of the subscriber profile from the home network to the visited network is also difficult as international standards need to be agreed and every operator needs to implement them.